Final answer:
ATP is the primary molecule for storing and providing energy for cellular work. Glucose must be transformed into ATP to be utilized effectively by the cells, and ADP contains less energy until it is converted back to ATP.
Step-by-step explanation:
The main energy-carrying molecule used to power cellular work is adenosine triphosphate (ATP). ATP is essential for storing energy for use by body cells. While glucose is a key source of energy, it must first be converted into ATP to be used by cells. Similarly, ADP (adenosine diphosphate) can be converted to ATP, but on its own, it has less potential energy compared to ATP. Therefore, the correct answer to the question is b) ATP.
When ATP is hydrolyzed into ADP + phosphate, the energy released is used for various cellular activities. During cellular respiration, glucose is broken down, and the energy released is used to form ATP from ADP and phosphate, making ATP the primary molecule in which energy is temporarily stored and made available for cellular work.